1. Field of Invention
The invention is directed to fracturing tools for use in oil and gas wells, and in particular, to fracturing tools having two moveable sleeves capable of providing two operational positions so that the fracturing tool can fracture the formation in the first operational position and then be moved, without well intervention, to the second operational position to produce return fluids from the well.
2. Description of Art
Fracturing or “frac” systems or tools are used in oil and gas wells for completing and increasing the production rate from the well. In deviated wellbores, particularly those having longer lengths, fracturing fluids can be expected to be introduced into the linear, or horizontal, end portion of the well to frac the production zone to open up production fissures and pores therethrough. For example, hydraulic fracturing is a method of using pump rate and hydraulic pressure created by fracturing fluids to fracture or crack a subterranean formation.
In addition to cracking the formation, high permeability proppant, as compared to the permeability of the formation, can be pumped into the fracture to prop open the cracks caused by a first hydraulic fracturing step. For purposes of this disclosure, the proppant is included in the definition of “fracturing fluids” and as part of well fracturing operations. When the applied pump rates and pressures are reduced or removed from the formation, the crack or fracture cannot close or heal completely because the high permeability proppant keeps the crack open. The propped crack or fracture provides a high permeability path connecting the producing wellbore to a larger formation area to enhance the production of hydrocarbons.
One result of fracturing a well is that the return fluids, e.g., oil, gas, water, that are sought to be removed from the well are mixed with sand and other debris broken loose in the formation. As a result, after fracturing, an intervention step is performed to reorient a downhole tool such as a frac tool so that the return fluids are passed through a screen or other device to filter out the sand and debris. This intervention step usually involves dropping a ball or other plug element into the well to isolate a portion of the well or to actuate the frac tool to move an actuator to open a fluid flow path through the screen and closes a fluid flow path through which the fracturing fluid was previously injected into the well or well formation.